Forward and backward prediction in ADPCM over nonideal channels
Abstract
Both forward and backward predictions have been demonstrated to produce highly intelligible, good-quality speech when used in adaptive DPCM systems at 16 kilobits/sec. However, when channel errors are introduced, the performance of these systems can deteriorate substantially. For forward protection, the use of a Hamming code to error-protect the transmitted coefficients is proposed. For backward prediction, channel error effects are much more severe; two different approaches to reducing this problem are proposed. One approach employs Hamming codes or punctured convolutional codes to encode the residuals. In the other approach, the transmitted error signal is coarsely quantized in the prediction loop to reduce the long-term effects of transmission errors.
- Publication:
-
ICC 1980; International Conference on Communications, Volume 3
- Pub Date:
- 1980
- Bibcode:
- 1980icc.....3R..42G
- Keywords:
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- Adaptive Filters;
- Channels (Data Transmission);
- Prediction Analysis Techniques;
- Pulse Code Modulation;
- Pulse Communication;
- Error Signals;
- Feedback Control;
- Long Term Effects;
- Signal Processing;
- Communications and Radar